LeetCode – Refresh – Regular Expression Matching

Do not confused with check if (*p == '\0') return *s == '\0';

p is the format that used to match. If p is already reaching end, s still has some chars left, they can not match.

class Solution {
public:
    bool isMatch(const char *s, const char *p) {
        if (*p == '\0') return *s == '\0';
        if (*(p+1) != '*') return (*s == *p || *s != '\0' && *p == '.') && isMatch(s+1, p+1);
        while (*s == *p || *s != '\0' && *p == '.') {
            if (isMatch(s, p+2)) return true;
            s++;
        }
        return isMatch(s, p+2);
    }
};